Fast Stent Retrieval Improves Recanalization Rates of Thrombectomy: Experimental Study on Different Thrombi

BACKGROUND AND PURPOSE: About 20% of patients with acute ischemic stroke due to large-artery occlusion do not achieve recanalization with mechanical thrombectomy. We aimed to determine whether the speed of retrieval of the stent retriever influences the efficacy in removing different clot types. MATERIALS AND METHODS: Sixty mechanical thrombectomies were performed using an in vitro pulsatile cerebrovascular circulation model with controlled pressure and flow rate. Experiments were dichotomized into fast and slow retrieval using a wedging technique, in which the stent retriever and distal catheter are retrieved together. We used 3 different clot types: erythrocyte-rich, fibrin-rich, and friable clots. Primary end points were complete (TICI 3) and successful (TICI 2b?3) recanalizations. Secondary measures were distal and new territory embolizations. RESULTS: Fast retrieval was more frequently associated with complete (RR?=?1.83; 95% CI, 1.12?2.99) and successful recanalization (RR?= 1.50; 95% CI, 1.03?2.19) than slow retrieval, without a difference in distal embolization (RR?= 0.75; 95% CI, 0.29?1.90). There were no emboli in a new territory. The advantage of fast retrieval over slow retrieval differed according to the clot composition, with a stronger effect with fibrin-rich clots with regard to complete (RR?= 4.00; 95% CI, 1.11?14.35; Pint?= .04) and successful (Pint?=?.10) recanalization. CONCLUSIONS: In our experimental model, a fast removal improved recanalization rates of mechanical thrombectomy, especially in the case of fibrin-rich clots. An in vivo confirmation is warranted to see whether our findings can have an impact in clinical practice.